L07: Electric Light Quality

(2 points)

INTENT

Enhance visual comfort and minimize flicker using electric lighting.

SUMMARY

This WELL feature requires projects to take into account characteristics of electric light used in the space such as color rendering, color quality and flicker. 

ISSUE

Humans have evolved to depend on the sun as the main and ideal source of light. Humans are tuned to the color rendering provided by daylight and recognize colors in association with daylight. Color can impact peoples' cognition and behavior. Using electric light with high color rendering can improve people's perception of a space, and low color rendering can impact the ability to differentiate between objects and perceive the surroundings accurately. 

Electric lighting used indoors also has low frequencies of flicker that are not present in daylight. Flicker has been associated with eye strain, headaches, migraines and epileptic seizures. In 2016, migraines accounted for 16 million disability adjusted life years (DALYs) in men and 30 million DALYs in women.

SOLUTIONS

Identifying and utilizing lighting fixtures that emit a high quality of light and do not display signs of flicker contributes to a comfortable and healthy space. Light fixtures with higher color rendering emit light that show colors realistically. Color Rendering Index (CRI) and IES TM-30-15 are commonly used metrics used to determine the color rendering properties of a light source. 

IMPACT

Using light sources that have characteristics similar to daylight can improve the comfort and well-being of users in a space and contribute to creating a healthy environment.

REQUIREMENTS

Part 1

Ensure Color Rendering Quality (1 point)

Verified by Architect

For All Spaces except Circulation Areas

Electric lighting meets at least one of the following color rendering requirements in occupiable spaces. Decorative fixtures, emergency lights and other special-purpose lighting may be excluded from these requirements.

1. Electric lighting meets one of the following requirements:

   Metric	Threshold
   CRI	CRI  ≥ 90
   CRI, R9	CRI  ≥ 80 with R9  ≥ 50
   IES TM-30-18	IES Rf ≥ 78, IES Rg ≥ 100, -1% ≤ IES Rcs,h1 ≤ 15%

For Circulation Areas

Electric lighting meets at least one of the following color rendering requirements. Decorative fixtures, emergency lights and other special-purpose lighting may be excluded from these requirements.  

1. Electric lighting meets one of the following requirements:

   Metric	Threshold
   CRI	CRI  ≥ 80
   IES TM-30-18	IES Rf ≥ 78, IES Rg ≥ 98, -7% ≤ IES Rcs,h1 ≤ 15%

Part 2

Manage Flicker (1 point)

Verified by Architect

For All Spaces

All electric lights (except decorative lights, emergency lights and other special-purpose lighting) used in regularly occupied spaces meet at least one of the following requirements for flicker:

1. A minimum frequency of 90 Hz at all 10% light output intervals from 10% to 100% light output.

2. LED products with a “low risk” level of flicker (light modulation) of less than 5%, especially below 90 Hz operation as defined by IEEE standard 1789-2015 LED.

© International WELL Building Institute